1. Field
One or more embodiments of the present invention relate to the field of display devices and more particularly to a display device comprising integrated photovoltaic cells.
2. Discussion of Related Art
Photovoltaic cells or solar cells are commonly implemented in modern electronic devices to provide an alternative source of energy. In display devices, such as the liquid crystal display (LCD), photovoltaic cells have been integrated into the LCD to harvest electrical energy from ambient light or light generated from a backlight source.
FIG. 1 illustrates a cross-sectional view of a conventional LCD 100 in an unassembled configuration. The LCD 100 comprises a white light source 120, and a horizontal polarizer 131 over the white light source 120. Photovoltaic cells 171, 172, 173 are formed above the horizontal polarizer 131. A pixel 140 comprising subpixels 141, 142, 143 is formed above the photovoltaic cells 171, 172, 173. Color filters 151, 152, 153 are formed on the subpixels 141, 142, 143. The color filters 151, 152, 153 can be made of a red filter 151, a green filter 152, and a blue filter 153 to create a multi-color pixel. A vertical polarizer 132 is formed on the color filters 151, 152, 153. A glass screen 160 is formed on the front vertical polarizer 132.
Typically, the photovoltaic cells 171, 172 173 are formed behind the pixel 140. The photovoltaic cells 171, 172, 173 are able to absorb most of the white light 30 emitted from the white light source 120 when the LCD 100 is turned on. The photovoltaic cells 171, 172, 173 are made of transparent or semi-transparent material so that the emitted white light 30 can be transmitted to the pixel 140. However, one drawback of this configuration is the photovoltaic cells 170 not being able to absorb the ambient light 20 effectively. The intensity of ambient light 20 is significantly reduced after passing through the front vertical polarizer 132, the color filters 151, 152, 153 and the subpixels 141, 142, 143, thus resulting in the photovoltaic cells 170 absorbing only a small amount of ambient light.